1. Field of the Invention
The present invention relates to an image pick-up device unit having an image pick-up device for obtaining an image signal corresponding to light irradiated on a photoelectrically converting surface thereof or a camera having the image pick-up device unit. More particularly, the present invention relates to the improvement of a camera, such as an interchangeable single-lens reflex digital camera.
2. Description of the Related Art
Recently, digital cameras such as a so-called digital still camera or a digital video camera (hereinafter, referred to as a digital camera or simply referred to as a camera) are generally put into practical use and are widely spread. In the digital cameras, a subject image formed based on beams from a subject (hereinafter, referred to as subject beams), which are transmitted through a photographing optical system (also referred to as a photographing lens) is formed onto a photoelectrically converting surface of a solid image pick-up device arranged at a predetermined position, such as a CCD (Charge Coupled Device, hereinafter, simply referred to as an image pick-up device). Further, an electrical image signal or the like representing a desired subject image is generated by using an photoelectrically converting action of the image pick-up devices. A signal based on the image signal and the like are outputted to a predetermined display device such as an LCD (Liquid Crystal Display) and an image or the like is displayed. The image signal or the like generated by the image pick-up device is recorded to a predetermined recording area of a predetermined recording medium as predetermined-format image data. Further, the image data recorded to the recording medium is read and the image data is converted to become an image signal which is optimum for a display using the display device. Thereafter, an image corresponding thereto is displayed based on the processed image signal.
In general, digital cameras have an optical finder device for observing, prior to a photographing operation, a desired subject as a photographing target and for setting a photographing range including the subject.
In general, a so-called single-lens reflex finder device is used as the optical finder device. In this single-lens reflex finder device, the advancing direction of the subject beams transmitted through the photographing optical system is bent by using a reflecting member arranged on the optical axis of the photographing optical system such that the subject image for observation is formed at a predetermined position. On the other hand, upon the photographing operation, the reflecting member is evacuated from the optical axis of the photographing optical system, thereby guiding the subject beams onto a light receiving surface of the image pick-up device, that is, onto a photoelectrically converting surface thereof and forming the subject image for photographing on the photographically converting surface.
Furthermore, recently, a so-called interchangeable lens digital camera having the single-lens reflex finder device is generally put into practical use. In the interchangeable lens digital camera, the photographing optical system is detachable to a camera main body, and a plurality of types of the photographing optical systems are selectively used in the single-camera main body by arbitrarily detaching and exchanging a desired photographing optical system in accordance with user's desire.
In the above-mentioned interchangeable lens digital camera, dust and the like floating in the air possibly enter the camera main body upon detaching the photographing optical system from the camera main body. Various mechanisms which are mechanically operated such as a shutter and a stop mechanism are arranged in the camera main body and thus, dangerously, the dust is possibly generated from the various mechanisms during the operation.
Upon detaching the photographing optical system from the camera main body, the light receiving surface (also referred to as the photoelectrically converting surface) of the image pick-up device arranged in the rear of the photographing optical system is exposed in the ambient air of the camera. Therefore, dust and the like are adhered to the photographing converting surface of the image pick-up device due to electric charge action and the like.
Then, for the conventional single-lens reflex digital cameras, for example, Japanese Unexamined Patent Application Publication No. 2000-29132 proposes a technology for suppressing the adhesion of dust and the like on the light receiving surface of the image pick-up device due to the electric charge action.
Means disclosed in Japanese Unexamined Patent Application Publication No. 2000-29132 suppresses the adhesion of dust and the like onto the light receiving surface of the image pick-up device due to the electric charge action by providing a transparent electrode onto the surface of a cover member for covering the light receiving surface of the image pick-up device provided in the camera and by applying to the transparent electrode a DC voltage or an AC voltage with several kHz to 20 kHz.
The means for neutralizing electric charges generated to the image pick-up device disclosed in the above publication suppresses the adhesion of dust and the like onto the light receiving surface of the image pick-up device due to static electricity.
On the other hand, as the image pick-up device in the conventional digital cameras, a packaged image pick-up device (e.g., referred to as a packaged CCD) is widely used. In addition to the above-mentioned image pick-up device, recently, the supply of a so-called bare CCD chip is proposed.
For example, Japanese Unexamined Patent Application Publication No. 9-130654 discloses means for shaking off dust and the like which are adhered to the photoelectrically converting surface by providing a member for vibration such as a piezoelectric element between the bare chip CCD and a substrate on which the bare chip CCD is placed and by applying a predetermined voltage to the member for vibration because dust and the like are much likely to adhere onto the photoelectrically converting surface in the bare chip CCD in many cases.
However, the means disclosed in Japanese Unexamined Patent Application Publication No. 2000-29132 suppresses the adhesion of dust and the like by neutralizing electric charges of the electrostatically-charged image pick-up device. Consequently, the means is not optimum as means for removing dust which is adhered or deposited to the photoelectrically converting surface of the image pick-up device, irrespective of the static electricity.
Moreover, the means disclosed in Japanese Unexamined Patent Application Publication No. 9-130654 can not be optimally applied to the image pick-up device such as the packaged CCD generally used for the conventional digital cameras because the means is devised in view of the bare chip CCD.
In other words, when the means disclosed in Japanese Unexamined Patent Application Publication No. 9-130654 is applied to the general packaged CCD or the like, vibrations to the image pick-up device or the package are applied. Thus, there is a possibility that the vibrating action adversely influences on various mechanisms arranged to the image pick-up device and near it, for example, causes the deterioration in mechanisms and the occurrence of errors.